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5.7 cam choice help

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  • 5.7 cam choice help

    Rebuilding a 5.7 due to a dropped valve. Currently has a 4bbl but will be doing a vortec head/intake swap. I mentioned in another thread that I was going to run a lt-4 hot cam and it was mentioned this wan;t a good choice due to exhaust reversion.
    cam specs are:
    Cam Style Hydraulic roller tappet
    Basic Operating RPM Range 1,800-5,800
    Intake Duration at 050 inch Lift 218
    Exhaust Duration at 050 inch Lift 228
    Duration at 050 inch Lift 218 int./228 exh.
    Advertised Intake Duration 279
    Advertised Exhaust Duration 287
    Advertised Duration 279 int./287 exh.
    Intake Valve Lift with Factory Rocker Arm Ratio 0.492 in.
    Exhaust Valve Lift with Factory Rocker Arm Ratio 0.492 in.
    Valve Lift with Factory Rocker Arm Ratio 0.492 int./0.492 exh.
    Lobe Separation (degrees) 112

    SO I am exploring other options how about GM #14097395 which is:
    Cam Style Hydraulic roller tappet
    Intake Duration at 050 inch Lift 196
    Exhaust Duration at 050 inch Lift 206
    Duration at 050 inch Lift 196 int./206 exh.
    Advertised Intake Duration 288
    Advertised Exhaust Duration 308
    Advertised Duration 288 int./308 exh.
    Intake Valve Lift with Factory Rocker Arm Ratio 0.431 in.
    Exhaust Valve Lift with Factory Rocker Arm Ratio 0.451 in.
    Valve Lift with Factory Rocker Arm Ratio 0.431 int./0.451 exh.
    Lobe Separation (degrees) 109

    This seems pretty close to factory specs.

    Basically looking for something reliable, being able to use factory Alpha 1 through prop exhaust. and have about 300-325 H.P.

    is 14097395 acceptable for this ? any other suggestions?


  • #2
    Re: 5.7 cam choice help

    I also like crane 109811 which is 204/214 I/E at .050 lift .429/.452 with a 112 LSA.

    I would be all of this as it is alittle more aggresive than stock but not crazy except it seems the price is over 400.00 thoughts?

    Comment



    • #3
      Re: 5.7 cam choice help

      Originally posted by aldfaa View Post
      Rebuilding a 5.7 due to a dropped valve. Currently has a 4bbl but will be doing a vortec head/intake swap. I mentioned in another thread that I was going to run a lt-4 hot cam and it was mentioned this wan;t a good choice due to exhaust reversion.
      SO I am exploring other options how about GM #14097395 which is:
      Cam Style Hydraulic roller tappet
      Intake Duration at 050 inch Lift 196
      Exhaust Duration at 050 inch Lift 206
      Duration at 050 inch Lift 196 int./206 exh.
      Advertised Intake Duration 288
      Advertised Exhaust Duration 308
      Advertised Duration 288 int./308 exh.
      Intake Valve Lift with Factory Rocker Arm Ratio 0.431 in.
      Exhaust Valve Lift with Factory Rocker Arm Ratio 0.451 in.
      Valve Lift with Factory Rocker Arm Ratio 0.431 int./0.451 exh.
      Lobe Separation (degrees) 109

      This seems pretty close to factory specs.

      Basically looking for something reliable, being able to use factory Alpha 1 through prop exhaust. and have about 300-325 H.P.

      is 14097395 acceptable for this ? any other suggestions?

      That 2nd one is the factory Merc cam. It can usually be had for less than aftermarket roller cams. You would be at that hp range, measured at crank, not prop.

      Is this for a small, light, or fast boat, or a heavy one?

      Comment



      • #4
        Re: 5.7 cam choice help

        Boat is a 1996 celebrity 196 bow rider. NO idea on weight just a guess 3300 ibs???

        Comment



        • #5
          Re: 5.7 cam choice help

          That sounds like a runabout that you could go with more cam. More cam than stock, that you can feel, will mean more head work/springs, etc. You want a balanced package within the cost window that you want to spend. I lean toward stock like mods. A number of people here can advise on more performance type ones.

          Comment



          • #6
            Re: 5.7 cam choice help

            Sorry if this is a "jack", mod can move me if needed. I also have a 5.7 with pre vortec heads. But hey John, could that cam & head combination be stroked at some future time? Or does a longer stroke dictate other design items?
            Also with the smaller chambers in the vortec heads does one use more head gasket to avoid adding too much to compression ratio? Does the cam handle that issue? Or am I on a wrong track? I'm trying to understand all the interrelationships.
            1989 Baja Sunsport 196, Mercruiser 5.7, Alpha 1
            Moultonborough Neck, Lake Winnipesaukee, NH

            Comment



            • #7
              Re: 5.7 cam choice help

              if you've got a roller set up...

              http://www.compcams.com/Company/CC/c...?csid=201&sb=2
              Just another moron with a computer and too much time on his hands...

              typical rainy afternoon on the river... http://www.youtube.com/watch?v=8Izi3v75jTs

              more recent, amateur camera operator for sure!... http://www.youtube.com/watch?v=EHoXsQc6644

              Comment



              • #8
                Re: 5.7 cam choice help

                Originally posted by NHGuy View Post
                Sorry if this is a "jack", mod can move me if needed. I also have a 5.7 with pre vortec heads. But hey John, could that cam & head combination be stroked at some future time? Or does a longer stroke dictate other design items?
                Also with the smaller chambers in the vortec heads does one use more head gasket to avoid adding too much to compression ratio? Does the cam handle that issue? Or am I on a wrong track? I'm trying to understand all the interrelationships.
                um... spend money on better heads before buiding a stroked bottom end... and then if you do put a stroker kit in it, you'll have heads that will work...


                for anywhere near stock, heads are the number one limiting component that dictates the most performance you can get out of something... if you ever wna to make a lot more power than stock, vortec heads are marginal at best... nice gain over prevortec heads, and a great bang for the buck, but if you put a really good set of heads on a stock 350 bottom end, add a cam, intake carb and exhaust you would have to in either case, and it'll make more power throughout the rpm range than the same amount of money spent on a stroked bottom end and left with near stock heads... in my experience anyhow...
                Just another moron with a computer and too much time on his hands...

                typical rainy afternoon on the river... http://www.youtube.com/watch?v=8Izi3v75jTs

                more recent, amateur camera operator for sure!... http://www.youtube.com/watch?v=EHoXsQc6644

                Comment



                • #9
                  Re: 5.7 cam choice help

                  the beutiful thing about roller cams is you can get loads of lift without adding duration,its all about air flow ,find out what head will flow,then match it.carb,intake,exhaust,matching.then get cam to match, stay with stock or close duration,a close lobe seperation angle say 108 to 110 for bottom end power find out what your springs are good for and thats youir lift.

                  Comment



                  • #10
                    Sign up today
                    Re: 5.7 cam choice help

                    Originally posted by NHGuy View Post
                    Sorry if this is a "jack", mod can move me if needed. I also have a 5.7 with pre vortec heads. But hey John, could that cam & head combination be stroked at some future time? Or does a longer stroke dictate other design items?
                    Also with the smaller chambers in the vortec heads does one use more head gasket to avoid adding too much to compression ratio? Does the cam handle that issue? Or am I on a wrong track? I'm trying to understand all the interrelationships.
                    Depends what 350 you are starting with. Most post '87's have recessed pistons and 64cc crate engine heads, so vortecs are no issue. The merc cam is used in the GM crate 383, but you would probably be better with a little larger flowing one. With a 383 spend some time getting the right crank, rods, and pistons. The D style pistons and making sure you keep the static compression ratio in the low 9's: 1 will be good.

                    Comment


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